KR102641880B1 - Pigment dispersion for cosmetics, water-based liquid cosmetics using it - Google Patents

Abstract

Provided is a cosmetic pigment dispersion of the pigment Pigment Red 4 (C.I.12085) with excellent dispersibility and stability over time, and an aqueous liquid cosmetic suitable for hair dyeing using the same. This pigment dispersion for cosmetics contains at least water, a water-soluble organic solvent, pigment of Pigment Red 4 (C.I.12085), and (ethyl betaine methacrylate/acrylate) copolymer, and is added to all solvents of water. It is characterized by a ratio of 30 to 95 mass%.

Description

Pigment dispersion for cosmetics, water-based liquid cosmetics using it

The present invention relates to a pigment dispersion for cosmetics with excellent dispersibility and stability over time of the pigment Pigment Red 4 (C.I.12085, Japanese legal pigment: Red No. 228), and to an aqueous liquid cosmetic using the same.

Since pigments have excellent hiding properties, color development, etc., many pigments containing pigments have been used as coloring materials in cosmetics such as temporary hair dyes and makeup cosmetics. Additionally, amphoteric polymer resins are widely used as resins added to cosmetics such as hair dyes.

On the other hand, the pigment Pigment Red 4 (Red No. 228) is called by the common name “Permatone Red” (C.I.12085, D&C Red 36) and is used as a coloring material in cosmetic compositions such as makeup cosmetics and hair dyes. This dispersion takes time to disperse, and the current situation is that the production of the dispersion has problems such as low productivity and stability over time.

On the other hand, in liquid cosmetics containing pigments, for example, the following 1) to 5) are known as prior art documents that mention dispersibility, stability over time, etc.

1) A color hair cosmetic containing water as the main solvent, an acrylic amphoteric polymer resin of a specific structure, an acid dye, and carbon black has been disclosed (for example, see Patent Document 1). While this acrylic amphoteric polymer resin forms a solid resin film on the hair, it is pointed out as a problem in that it is poor in washing with shampoo and has a strong stiff feel. Additionally, when dyes and pigments are used together, the viscosity of the cosmetics tends to increase after aging, which is also cited as a drawback.

2) An alcohol-based main solvent with a carbon number of 4 or less, and an acrylic amphoteric polymer resin as a dispersant, N-methacryloylethyl-N,N-dimethylammonium·α-N-methylcarboxybetaine·butyl methacrylate copolymer. A temporary hair dye containing titanium black as a coloring ingredient has been disclosed (for example, see Patent Document 2). Here, in addition to titanium black, red No. 228 (C.I.12085) is included as a pigment that may be added. In this case, the increase in viscosity is suppressed, but there is no specific mention of the addition of organic pigments such as Pigment Red 4 (C.I.12085: Red No. 228).

3) A temporary hair dye containing ethanol as the main solvent, black titanium oxide, (methacryloyloxy ethylcarboxybetaine/alkyl methacrylate) copolymer, hydroxypropyl cellulose, and glycerin has been disclosed. (For example, see Patent Document 3). This patent document 3 also lists Pigment Red 4 (C.I.12085: Red No. 228) as a pigment that may be added in addition to titanium black. In the case of this document, the viscosity of the cosmetic is relatively high to very high viscosity, at 500,000 to 30,000 mPa·sec as measured by a B-type viscometer, and Pigment Red 57 (C.I.15850: Red No. 202) and Pigment Yellow 1 ( There is an example of the inclusion of C.I.11680: Yellow No. 401), but there is no specific mention of the addition of Pigment Red 4 (C.I.12085: Red No. 228).

4) A hair coloring composition containing a branched polyglycerin-modified silicone of a specific structure, a betaine-modified silicone, and a film-forming resin, and which may also contain an organic pigment is disclosed (for example, see Patent Document 4). . Additionally, (methacryloyloxy ethylcarboxybetaine/alkyl methacrylate) copolymer and Acid Black 1 (C.I.20470: Black No. 401), Acid Violet No. There is an example of the combined use of 43 (C.I.60730: Purple No. 401) and Acid Orange 7 (C.I.15510: Orange No. 205), but there is no specific mention of the addition of Pigment Red 4 (C.I.12085: Red No. 228). will be.

5) A liquid cosmetic containing sepiomelanin, an amphoteric compound, and water has been disclosed (for example, see Patent Document 5). This liquid cosmetic uses water as the main solvent, and there is an example of using Yuca former ((methacryloyloxy ethylcarboxybetaine/alkyl methacrylate) copolymer) to disperse sepiomelanin, but Pigment Red 4 There is no special mention about the addition of organic pigments, including (C.I.12085, Red No. 228).

Patent Document 1: Japanese Patent Laid-Open No. 10-273431 (scope of claims, examples, etc., summary) Patent Document 2: Japanese Patent Application Publication No. 9-208436 (scope of patent claims, paragraph [0012], etc.) Patent Document 3: Japanese Patent Application Publication No. 2008-63251 (scope of patent claims, paragraph [0028], etc.) Patent Document 4: Japanese Patent Application Publication No. 2008-308435 (scope of claims, examples, etc.) Patent Document 5: Japanese Patent Application Publication No. 2001-181128 (scope of claims, examples, etc., summary)

Here, the present invention seeks to solve the above-described conventional problems, etc., by providing a cosmetic pigment dispersion with excellent dispersibility and stability over time of Pigment Red 4 (C.I.12085, Red No. 228), which is a pigment, and a hair dye using the same. The purpose is to provide an aqueous liquid cosmetic suitable for the like.

As a result of careful study of the above-described conventional problems, the present inventors have found that it contains at least water, a water-soluble organic solvent, a pigment of Pigment Red 4 (C.I.12085, Red No. 228), and specific components, and contains water. It was discovered that by setting the ratio to the total solvent within a specific range, an aqueous liquid cosmetic suitable for the above-mentioned cosmetic pigment dispersion, hair dye using the same, etc. could be obtained, and the present invention was completed.

That is, the pigment dispersion for cosmetics of the present invention contains at least water, a water-soluble organic solvent, pigment of Pigment Red 4 (C.I.12085, Red No. 228), and (ethyl betaine methacrylate/acrylate) copolymer. It contains and is characterized in that the ratio of water to the total solvent is 30 to 95% by mass.

It is preferable that the water-soluble organic solvent is a lower alcohol having 5 or less carbon atoms.

It is preferable that the lower alcohol is ethanol.

The water-based liquid cosmetic of the present invention is characterized by containing the pigment dispersion for cosmetics.

It is preferable that the ratio of water to the total solvent of the aqueous liquid cosmetic is 30 to 95% by mass.

In the water-based liquid cosmetic, it is preferable that a lower alcohol with 5 or less carbon atoms is included in addition to water.

The lower alcohol of the water-based liquid cosmetic is preferably ethanol.

According to the present invention, a pigment dispersion for cosmetics with excellent dispersibility and stability over time of Pigment Red 4 (C.I.12085, Red No. 228), a pigment, and an aqueous liquid cosmetic suitable for hair dyes using the same are provided.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described in detail.

The pigment dispersion for cosmetics of the present invention contains at least water, a water-soluble organic solvent, a pigment of Pigment Red 4 (C.I.12085), and a (ethyl betaine methacrylate/acrylate) copolymer, and is comprised of water as a whole. It is characterized by a ratio to solvent of 30 to 95 mass%.

The pigment of Pigment Red 4 (CI12085, D&C Red 36) used in the present invention is a colorant (Red No. 228) among the legal pigments generally used in cosmetics in Japan. This pigment is a red powder, common name "Permatone Red"(D&C Red 36) [1-(2-chloro-4-nitrophenylazo)-2-naphthol (C ₁₆ H ₁₀ ClN ₃ O ₃ : Molecular weight 327.72)].

This aqueous dispersion of Pigment Red 4 (C.I.12085) requires dispersion time and has problems such as low productivity and stability over time when producing the dispersion. becomes resolved.

The content of Pigment Red 4 (C.I.12085) to be used is preferably 1 to 32% by mass, more preferably, based on the total amount of pigment dispersion for cosmetics, from the viewpoint of stability after dispersion and convenience of cosmetic production, It is preferable to set it as 2-25 mass%.

By setting the content of Pigment Red 4 (C.I.12085) to 1% by mass or more, productivity is excellent and coloring properties when added to cosmetics are excellent. On the other hand, by setting it to 32% by mass or less, dispersibility and stability over time are improved. This gets even better.

The water-soluble organic solvent used in the present invention is used as a solvent for pigment dispersions for cosmetics, and includes lower alcohols having 5 or less carbon atoms. Specifically, methyl alcohol (methanol), ethyl alcohol (ethanol), n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, pentyl alcohol, ethylene glycol, At least one type (each type alone or a mixture of two or more types), such as propylene glycol, can be mentioned.

In particular, from the viewpoint of safety, handling, etc., the use of ethyl alcohol (ethanol) is preferable.

The content of the water-soluble organic solvent used is determined from the viewpoint of the dissolved stability of the (ethyl betaine methacrylate/acrylate) copolymer described later and the stability of the pigment dispersion, especially stability at low temperatures, in the cosmetic pigment dispersion. With respect to the total amount, it is preferably 1.0 to 60.0 mass%, more preferably 5.0 to 30.0 mass%.

By setting the content of this water-soluble organic solvent to 1.0% by mass or more, it is possible to exert an effect in preventing freezing at low temperatures of the solvent, and furthermore, to a small extent, a preservative effect is exerted. On the other hand, by setting it to 60.0% by mass or less, the (described later) The dissolved stability of the ethyl betaine/acrylate methacrylate copolymer becomes better.

The (ethyl betaine methacrylate/acrylate) copolymer used in the present invention is a component that improves the dispersibility of Pigment Red 4 (C.I.12085) and its stability over time when used as a dispersion.

This (ethyl betaine methacrylate/acrylate) copolymer is a copolymer of ethyl betaine methacrylate and two or more monomers consisting of acrylic acid, methacrylic acid, or simple esters thereof. The common name is N-methacrylate. It is a loyloxyethyl-N,N-dimethylammonium-α-N-methylcarboxybetaine-methacrylic acid alkyl ester copolymer, and has a betaine unit in the polymer structure. Polymers with this betaine unit have different ionic properties. Unlike polymers, it exhibits unique behavior.

Conventionally, (ethyl betaine methacrylate/acrylate) copolymer is an ingredient used as a film forming agent and hair styling agent, but in the case of the present invention, the dispersibility and dispersion of Pigment Red 4 (C.I.12085) It is an ingredient that improves stability over time when used as an ingredient that enables new uses.

As commercially available copolymers (ethyl betaine methacrylate/acrylate), RAM Resin-1000 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), Plus Size L-440 (manufactured by Kuu Chemical Industry Co., Ltd.), etc. can be used.

The content of the (ethyl betaine methacrylate/acrylate) copolymer used is based on the entire amount of the pigment dispersion for cosmetics since it ensures good dispersibility of Pigment Red 4 (C.I.12085) and stability over time when used as a dispersion. Regarding the solid content, it is preferably 3.0 to 15.0 mass%, more preferably 5.0 to 10.0 mass%.

By setting the content of this (ethyl betaine methacrylate/acrylate) copolymer to 3.0% by mass or more, the dispersion state of the pigment becomes stable and the fixation of the pigment, etc. when mixed into cosmetics becomes good. By setting it to 15.0% by mass or less, the convenience of producing cosmetics becomes more improved by suppressing the increase in viscosity.

In the present invention, more preferably, the mixing ratio of Pigment Red 4 (C.I.12085) and (ethyl betaine methacrylate/acrylate) copolymer to be used is, in mass ratio, Pigment Red 4 (C.I.12085) ): (ethyl betaine methacrylate/acrylate) copolymer = preferably 1:1 to 4:1, particularly preferably 2:1 to 4:1.

By setting this ratio to 1:1 to 4:1, it becomes a pigment dispersion for cosmetics that is more compatible with the dispersibility and stability over time of Pigment Red 4 (C.I.12085).

As water used as a solvent in the present invention, distilled water, ion-exchanged water, purified water, pure water, ultrapure water, etc. can be used, and the ratio of water to the total solvent (water + water-soluble organic solvent) is 30 to 95% by mass (0.30 to 0.30% by mass). 0.95), and preferably 60 to 95% by mass.

If the ratio of water to the total solvent is less than 30% by mass (0.30), the stability over time becomes unstable and dispersion of the pigment becomes impossible. On the other hand, if it is more than 95% by mass (0.95), the original content of each component is reduced. It cannot be manufactured because it contains solvents other than water.

The pigment dispersion for cosmetics of the present invention contains the above water-soluble organic solvent, Pigment Red 4 (C.I.12085), (ethyl betaine methacrylate/acrylate) copolymer, and water, but additionally improves dispersibility and contains each component. From the viewpoint of dissolved stability, pH adjusters, surfactants, viscosity adjusters, chelating agents, etc. can be appropriately used as needed.

In addition, the preparation of the pigment dispersion for cosmetics of the present invention includes each component such as the water-soluble organic solvent, Pigment Red 4 (C.I.12085), (ethyl betaine methacrylate/acrylate) copolymer, and water in the above amounts. It can be manufactured by mixing in the range of and stirring and mixing uniformly.

For example, after stirring Pigment Red 4 (C.I.12085) and a solvent such as water-soluble solvent or water with a general-purpose disper until uniform, mix the (ethyl betaine methacrylate/acrylate) copolymer. After this, the pigment dispersion liquid for cosmetics can be prepared by further stirring with a homomixer or the like until it becomes uniform with a disper or the like.

The pigment dispersion for cosmetics of the present invention configured in this way can solve problems such as long dispersion time and low stability over time in the pigment Pigment Red 4 (C.I.12085), and A pigment dispersion for cosmetics with excellent dispersibility of Mont Red 4 (C.I.12085) and excellent stability over time can be obtained.

The obtained pigment dispersion for cosmetics is suitable for use in cosmetics using Pigment Red 4 (C.I.12085), such as skin care cosmetics, hair cosmetics, water-limiting cosmetics, makeup cosmetics, ultraviolet ray protection cosmetics, and nail cosmetics. Preferred examples include emulsions, creams, lotions, sunscreens, tanning agents, acne countermeasure cosmetics, basic cosmetics such as essence, foundation, eye shadow, eyeliner, eyebrows, mascara, blusher, Examples include nail colors, treatment nails, various gel nails, makeup cosmetics such as lipsticks, rinses, conditioners, hair colors, set hair restorers, deodorants, perfumes, etc. Additionally, there is no particular limitation on the form of the product, but since it is a dispersion (aqueous form), it can be applied to aqueous forms such as liquid, emulsion, cream, paste, gel, mousse, and spray.

In particular, in terms of the dispersion characteristics of the pigment dispersion for cosmetics of the present invention, it is preferable to use it in water-based liquid cosmetics, such as hair dyes (including eyeliner and mascara), and water-based nail colors.

As a specific embodiment of the water-based liquid cosmetic of the present invention, use as a hair dye will be described below.

The hair dye that can be used includes a cosmetic pigment dispersion containing the above Pigment Red 4 (C.I.12085), general-purpose hair dye ingredients such as resin, lower alcohol, hair dye aid, pH adjuster, and water. In addition, depending on the color variation of the hair dye, colorants other than Pigment Red 4 (C.I.12085) may be included as needed.

The content of the pigment dispersion for cosmetics containing Pigment Red 4 (C.I.12085) is 0.5 to 30.0% by mass based on the total amount of hair dye, from the viewpoint of hair dyeing effect, solubility, storage stability, etc. Preferred, more preferably 1.0 to 25.0% by mass.

As colorants other than Pigment Red 4 (C.I.12085) that can be used, pigments generally used in hair dyes can be used. For example, inorganic pigments include carbon black, titanium black oxide, iron sulfate, and black acid. Examples include red iron, bengala, ultramarine blue, navy blue, chromium oxide, chromium hydroxide, carmine, and shikonin, and as organic pigments, Red No. 2 (Acid Red 27: C.I.16185), Red No. 3 (Acid Red 51: C.I.45430), Red No. 102 (Acid Red 18: C.I.16255), Red No. 104 (1) (Acid Red 92: C.I.45410), Red No. 105 (1) (Acid Red 94: C.I.45440), Red No. 106 (Acid Red 52: C.I.45100), Red No. 227 (Acid Red 33: C.I.17200), Red No. 230 (1), Red No. 230 (2) (all Acid Red 87: C.I.45380) , Red No. 231 (Acid Red 92: C.I.45410), Red No. 232 (Acid Red 94: C.I.45440), Yellow No. 4 (Acid Yellow 23: C.I.19140), Yellow No. 5 (Food Yellow 3: C.I.15985), Yellow (1) of No. 202, (2) of Yellow No. 202 (all Acid Yellow 73: C.I.45350), Yellow No. 203 (Acid Yellow 3: C.I.47005), Green No. 3 (Food Green: C.I.42053), Green No. 201 (Acid Yellow) Green 25: C.I.61570), Green No. 204 (Solvent Green 7: C.I.59040), Green No. 205 (Acid Green 5: C.I.42095), Blue No. 1 (Food Blue 2: C.I.42090), Blue No. 2 (Acid Blue 74) : C.I.73015), Blue No. 202 (Acid Blue 5: C.I.42052), Blue No. 205 (Acid Blue 9: C.I.42090), Orange No. 205 (Acid Orange 7: C.I.15510), Orange No. 207 (Acid Red 95: C.I. 45425), barium, calcium, zirconium or aluminum lake pigments in water-soluble dyes such as brown No. 201 (acid orange 24: C.I.20170), red No. 201 (pigment red 57-1: C.I.15850), red No. 202 (pigment red) 57: C.I.15850), Red No. 203 (Pigment Red 53: C.I.15585), Red No. 204 (Pigment Red 53 (Ba): C.I.15585), Red No. 205 (Pigment Red 49 (Na): C.I.15630) , Red No. 206 (Pigment Red 49 (Ca): C.I.15630), Red No. 207 (Pigment Red 49 (Ba): C.I.15630), Red No. 208 (Pigment Red 49 (Sr): C.I.15630), Red Red No. 215 (Solvent Red 49: C.I.45170), Red No. 218 (Solvent Red 48: C.I.45410), Red No. 219 (Pigment Red 64: C.I.15800), Red No. 220 (Pigment Red 63 (Ca): C.I.15880) ), Red No. 221 (Pigment Red 3: C.I.12120), Red No. 223 (Solvent Red 43: C.I.45380), Red No. 225 (Solvent Red 23: C.I.26100), Red No. 226 (Bat Red 1: C.I.73360) , Yellow No. 201 (Acid Yellow 73: C.I.45350), Yellow No. 204 (Solvent Yellow 33: C.I.47000), Yellow No. 205 (Pigment Yellow 12: C.I.21090), Green No. 202 (Solvent Green 3: C.I.61565), Blue No. 201 (Bat Blue 1: C.I.73000), Blue No. 204 (Bat Blue 6: C.I.69825), Blue No. 404 (Pigment Blue 15: C.I.74160), Orange No. 201 (Solvent Red 72: C.I.45370), Orange Orange No. 203 (Pigment Orange 5: C.I.12075), Orange No. 204 (Pigment Orange 13: C.I.21110), Orange No. 206 (Solvent Red 73: C.I.45425), Orange No. 401 (Pigment Orange 1: C.I.11725), Orange No. 402 (Acid Orange 20: C.I.14600), Orange No. 403 (Solvent Orange 2: C.I.12100), Black No. 401 (Acid Black 1: C.I.20470), Purple No. 201 (Solvent Violet 13: C.I.60725), etc. available, and at least one of these can be used.

The content when using these colorants is 0.1 to 25.0% by mass based on the total amount of hair dye, from the viewpoint of hair dyeing effect, solubility, storage stability, etc.

Resins that can be used include those that have water resistance when dried and those that have film-forming properties, such as (methacryloyloxy ethyl carboxybetaine/alkyl methacrylate) copolymer, (octyl acrylamide/hydroxypropyl acrylate/butylaminoethyl methacrylate) copolymer, (hydroxyethyl acrylate/butyl acrylate/methoxyethyl acrylate) copolymer, N-methacryloylethyl-N,N-dimethyl At least one type such as ammonium/α-N-methylcarboxybetaine/butyl methacrylate copolymer and (ethyl betaine methacrylate/acrylate) copolymer can be mentioned.

The content of these resins is preferably 0.1 to 10.0% by mass in terms of solid content, preferably 0.5 to 5.0% by mass, based on the total amount of hair dye, from the viewpoint of water resistance, texture after hair application, applicability, etc. .

Lower alcohols that can be used can be preferably used from the viewpoint of low-temperature stability, drying properties, and hypoallergenic properties. Examples of the lower alcohol used include lower alcohols having 5 or less carbon atoms. Specifically, at least one of methyl alcohol (methanol), ethyl alcohol (ethanol), n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, and pentyl alcohol. Species (each alone or a mixture of two or more species) may be included.

In particular, from the viewpoint of safety, handling, etc., the use of ethyl alcohol (ethanol) is preferable.

The content of these lower alcohols is preferably 10 to 80% by mass, more preferably 15 to 70% by mass, and particularly preferably 15 to 65% by mass, based on the total amount of hair dye.

Hair dyeing aids that can be used are those used to further improve the hair dyeing effect, for example, benzyl alcohol, phenyl ethyl alcohol, phenoxyethanol, propylene carbonate, propylene glycol, ethoxydiglycol, N-methylpyrrolidone, At least one type such as N-methyl-2 pyrrolidone can be mentioned.

The content of these hair dye aids is preferably 2.0 to 20.0%, more preferably 5.0 to 15.0%, and especially preferably 5.0 to 15.0%, based on the total amount of hair dye, from the viewpoint of additional hair dyeing effect and color transfer prevention. is 3.0~5.0%.

The pH adjuster that can be used is used to improve colorability, prevent skin irritation, and prevent skin dyeing problems. It is preferable to adjust the pH of the hair dye to 2 to 5 with this pH adjuster, more preferably, pH It is desirable to adjust it to 3.5~5.0.

As a pH adjuster that can be used, for example, organic acids such as formic acid, acetic acid, lactic acid, tartaric acid, malic acid, citric acid, glycolic acid, inorganic acids or salts thereof, and in some cases, alkalis such as triethanolamine can be used. .

The remainder of the hair dye is adjusted with water (purified water, distilled water, ion-exchanged water, pure water, tap water, etc.).

As for this water content, the ratio of water to the total solvent (water + water-soluble organic solvent) is preferably 30 to 95 mass% (0.30 to 0.95), more preferably 30 to 80 mass%. do.

If the ratio of water to the total solvent is less than 30% by mass (0.30), the stability over time is poor, and the dissolved stability when water-soluble components are added is poor. On the other hand, if it is more than 95% by mass (0.95), There is a greater possibility that antibacterial properties will be poor.

The hair dye constituted in this way contains at least a cosmetic pigment dispersion containing Pigment Red 4 (C.I.12085), a resin, a lower alcohol, a hair dye aid, and a pH adjuster, but the effect of the present invention is not achieved. To the extent that it does not cause harm, other raw materials such as thickeners, various surfactants, preservatives, ultraviolet absorbers, antioxidants, reduction inhibitors, chelating agents, oil-based ingredients, fragrances, animal and plant extracts, etc. may be appropriately contained.

Thickeners that can be used include, for example, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, stearoxy hydroxypropyl methyl cellulose, and hydroxypropyl guar hydroxy in terms of applicability, storage stability, and suppression of pigment sedimentation. Examples include cellulose-based thickeners such as propyltrimonium chloride and cationized cellulose obtained by adding a cationic functional group to cellulose, resin-based thickeners such as polyvinyl alcohol and acrylic acid, and clay-based thickeners such as bentonite.

The viscosity of the hair dye provides an appropriate viscosity and dissolution stability of the dye, giving smoothness, softness, and moist feeling to the hair, improving the texture, improving water resistance, and further improving usability and applicability when used in coated materials. From the point of view of application to hair, the viscosity at 25°C (cone plate viscometer: 50 rpm) is 1.0 to 200 mPa·s, preferably 1.0 to 50 mPa·s, more preferably 4.0 to 4.0. It is desirable to set it to 10.0 mPa·s.

The viscosity range (1.0 to 200 mPa·s) can be adjusted by appropriately adjusting the amount of each component used, the type of thickener preferably used and its amount, etc.

By setting the viscosity of this hair dye to 1.0 mPa·s or more, it becomes less likely for liquid to leak from containers, etc., and it also becomes difficult for it to adhere to the scalp and will not contaminate clothes. On the other hand, if the viscosity is 200 mPa·s or less, By doing this, it becomes easier for the user to control the amount of liquid applied to the application material such as a brush, and it also becomes possible to spread it thinly and evenly on the hair.

The hair dye of the present embodiment can be prepared by a commercial method, and each component such as the cosmetic pigment dispersion containing Red No. 228, resin, lower alcohol, hair dye assistant, pH adjuster, and water is as described above. By mixing within the respective content ranges and further stirring and mixing uniformly using a suitable kneader, etc., a hair dye with the above-mentioned preferable viscosity and pH ranges can be produced.

For example, the alcohol phase such as resin and lower alcohol, the colorant containing Pigment Red 4 (C.I.12085), and the water phase such as water are each stirred with a general-purpose disper or the like until they become uniform, and then the alcohol phase is mixed. After mixing the aqueous phase, a pH adjuster, a thickener, etc. are additionally added, stirred with a disper or the like until uniform, and then stirred with a homomixer or the like to prepare the desired hair dye.

In providing for use the hair dye of the present embodiment configured as described above, a general-purpose hair applicator can be used, and the shape and structure of the hair applicator used are not particularly limited, for example, a knock-type valve. Examples include an applicator provided with a device, a hair mascara type applicator, a tube type applicator, and an applicator provided with a piston pressing mechanism.

The hair dye of the present embodiment configured as described above contains at least a cosmetic pigment dispersion containing Pigment Red 4 (C.I.12085), a resin, a lower alcohol, a hair dye auxiliary, a pH adjuster, and water, Pigment Red 4 (C.I.12085) has excellent dispersibility and stability over time, so it can stably disperse the coloring ingredients of hair dye, has excellent storage stability, water resistance, usability, applicability, low temperature stability, drying properties, and It is possible to obtain hair dyes with excellent polarity.

Example

Next, the present invention will be further described in detail through Examples and Comparative Examples, but the present invention is not limited by the following Examples.

[Examples 1 to 12 and Comparative Examples 1 to 4: Preparation of pigment dispersion for cosmetics]

A pigment dispersion for cosmetics was prepared by dispersing with a bead mill according to the formulation shown in Table 1 below.

For the obtained pigment dispersions for cosmetics of Examples 1 to 12 and Comparative Examples 1 to 4, the particle diameter and stability over time of the pigment dispersions for cosmetics were evaluated by the following evaluation method.

The results of these evaluations are shown in Table 1 below.

(Measurement of particle diameter of pigment dispersion for cosmetics)

For each of the obtained pigment dispersions for cosmetics, the particle diameter (histogram average particle diameter based on scattered light intensity distribution: D ₅₀ ) was measured using a particle size distribution measuring device [FPAR-1000 (manufactured by Otsuka Electronics)] at 25°C. did.

(Stability over time: 50℃, after 1 month)

Each of the obtained pigment dispersions for cosmetics was stored in a glass storage container with a cover, and each dispersion was left at 50°C for 1 month and evaluated using the following evaluation criteria.

Evaluation standard:

A: The particle diameter is stable at 200 nm or less (no sedimentation or aggregation, uniformly dispersed and stable).

B: Initially, the particle diameter exceeds 200 nm. Or the particle diameter increases over time.

C: gelation.

As is clear from the results in Table 1 above, Examples 1 to 12 of the present invention have good particle diameters and are excellent in both dispersibility and stability over time compared to Comparative Examples 1 to 4, which are outside the scope of the present invention. It has been confirmed.

[Examples 13 to 18 and Comparative Example 5: Adjustment of hair dye]

Using the respective pigment dispersions for cosmetics obtained above, hair dye was prepared by stirring according to the formulation shown in Table 2 below.

For each of the obtained hair dyes, the particle diameter and stability over time were measured using the above-mentioned measurement methods, and the viscosity, pH, dyeing properties, and drying properties were evaluated using the following evaluation methods.

These results are shown in Table 2 below.

(Method for measuring viscosity)

For each hair dye of Examples 13 to 18 and Comparative Example 5 obtained by the above method, the viscosity at 25°C (cone plate viscometer: viscosity at 50 rpm) was measured.

(Method of measuring pH)

The pH of each hair dye in Examples 13 to 18 and Comparative Example 5 obtained by the above method was measured at 25°C using a glass electrode pH meter.

(Evaluation method for dyeing properties)

0.2 g of each obtained hair dye was applied to human hair bundles (10 cm, 1 g) using a brush, dried at room temperature, and the dyeing state was sensory evaluated using the following evaluation criteria.

Evaluation standard:

A: It dyes well and the dyeing lasts.

B: It does not dye very well, but there is no color unevenness.

C: Does not dye well or has color unevenness.

(Evaluation method for dryness)

Each of the obtained hair dyes was applied to human hair bundles (10 cm, 1 g) using a brush, dried at room temperature, and evaluated based on the following evaluation criteria.

Evaluation standard:

A: After 5 minutes, no embolism occurs.

B: Color transfer occurs even after 5 minutes.

As is clear from the results in Table 2 above, compared to the dye in Examples 13 to 18, each of the dyes in Examples 13 to 18 had good viscosity and pH, good particle diameter, and excellent dispersibility and stability over time. It was confirmed that it was excellent in both dyeing properties and drying properties as a hair dye.

It is possible to obtain a cosmetic pigment dispersion of the pigment Pigment Red 4 (C.I.12085) with excellent dispersibility and stability over time, and an aqueous liquid cosmetic suitable for hair dye, etc. using the pigment dispersion.

Claims (7)

It contains at least water, a water-soluble organic solvent, a pigment of Pigment Red 4 (C.I.12085), and a (ethyl betaine methacrylate/acrylate) copolymer, and the ratio of water to the total solvent is 30 to 95 mass. Pigment dispersion for cosmetics, characterized in that %. In claim 1,
A pigment dispersion for cosmetics, characterized in that the water-soluble organic solvent is a lower alcohol having 5 carbon atoms or less. In claim 2,
A pigment dispersion for cosmetics, characterized in that the lower alcohol is ethanol. An aqueous liquid cosmetic comprising the cosmetic pigment dispersion according to any one of claims 1 to 3. In claim 4,
An aqueous liquid cosmetic, characterized in that the ratio of water to the total solvent of the aqueous liquid cosmetic is 30 to 95% by mass. In claim 5,
An aqueous liquid cosmetic, characterized in that the aqueous liquid cosmetic contains a lower alcohol having 5 or less carbon atoms in addition to water. In claim 6,
An aqueous liquid cosmetic, characterized in that the lower alcohol is ethanol.